鸟胚中的刚毛结构来自于被称为基板（placode）的微小皮肤细胞结构，基板顶端快速增殖的细胞环形成了刚毛的圆柱井结构。

In the bird embryo these bristles erupt from tiny patches of skin cells called placodes. A ring of fast-growing cells on the top of the placode builds a cylindrical wall that becomes a bristle.

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每个滤泡含有一个大量快速增殖的B细胞和吞噬细胞的构成的生发中心。

Each follicle contains a germinal center populated by rapidly proliferating B cells and macrophages.

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目的：研究甲肝病毒在细胞内快速连续传代培养病毒增殖情况，探索疫苗生产工艺改进的可能性。

Objective: to study the proliferation of HAV which were cultured rapidly and consecutively in cells, and to investigate the possibility of improving the production process of inactivated HAV vaccine.

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